An intelligent vertical handoff algorithm in heterogeneous wireless networks

To coordinate the various access technologies in the 4G-communication system, intelligent vertical handoff algorithms are required. This paper mainly deals with a novel vertical handoff decision algorithm based on fuzzy logic with the aid of grey theory and dynamic weights adaptation. The grey prediction algorithm (GPA) takes 4 sampled received signal strengths as input parameters, and calculates the predictive received signal strength in order to reduce the call dropping probability. The fuzzy logic theory based Quantitative Decision Algorithm takes 3 QoS metrics, received signal strength (RSS), available bandwidth (BW), and monetary cost(C) of candidate networks as input parameters. And the weight of each QoS metrics is adjusted along with the networks changing to trace the network condition. The final optimized vertical handoff decision is made by comparing the quantitative decision values of the candidate networks. Simulation results demonstrate that the proposed algorithm provides high performance in heterogeneous as well as homogeneous network environment.